Alan Moore's comic: a masterpiece of SF art

In a league of its own ... Detail of the cover of The League of Extraordinary Gentlemen by Alan Moore and Kevin O'Neill. Photograph: Knockabout Comics

The art of science fiction is currently on display in an exhibition at the British Library, London, where you can see a real-life Tardis – well, maybe not quite a real-life one, but it looks convincing from the outside – along with legions of book covers and illustrations that map the history of science fiction from Thomas More to China Miéville.

My favourite exhibit, partly because it is one of the most visually rewarding, is Alan Moore's comic The League of Extraordinary Gentlemen. Moore is the wild magician of British graphic fiction. You may love or loathe other works by him (such as From Hell), or be put off by the whole idea of adult comics that linger too long in an adolescent world of superheroes, or indeed want to avoid such cultural realms like the plague. But if there is one comic, indeed one contemporary work of science fiction that every literate adult should read, it is this one.

In the first two volumes of The League of Extraordinary Gentlemen, Moore and artist Kevin O'Neill reimagine London at the height of the British empire. They assemble a team of superheroes from late Victorian fiction, including adventurer Alan Quatermain from the novels of Rider Haggard and Mina Harker from Bram Stoker's Dracula. Together these fictional exemplars of Victorian courage face surreal threats that culminate in a tremendous recreation of The War of the Worlds in Volume Two. O'Neill's richly coloured fantastical pictures complement Moore's writing, which has never been more witty, erudite and resonant.

What makes Moore's comic so special? After all, the genre it belongs to, "steampunk" – that is, the fantastical sci-fi reinvention of Victoriana, is now well established, with Sherlock a brilliant new spin that puts a Victorian hero in modern London. For the sake of arcane argument I would claim that it actually originated in 1970s Dr Who, which often pitted Tom Baker against robot mummies in an Edwardian country house or a grotesque "homunculus" on the streets of 1890s Limehouse.

The special charm of The League ... lies in its knowledgable literary enthusiasm. Moore seems immersed in late-19th-century fantasy writing, and he evokes this world not through vague allusion but very accurate pastiche. The result is a masterpiece of the modern British novel – a comic worthy of a Booker prize. Now there's a thought.

A word of warning: if you do want to read it, start chronologically with Volume One. Moore has since returned to the series but with several strange twists. Black Dossier brings a more esoteric, magical edge to what started as his most accessible work. I can't help suspecting that here is the willfully underground soul of Moore rebelling against his own most mainstream publication. Yet like Arthur Conan Doyle, seemingly unable to kill off Sherlock Holmes, Moore has returned to his greatest characters, and Volume Three brings its apocalyptic vision steaming into the early 20th century.

The League of Extraordinary Gentlemen is a blazing world of the imagination and one of the triumphs of recent British fiction. No wonder they have it in the British Library among the illuminated manuscripts.